0.5 V, ultra low power multi standard Gm-C filter for biomedical applications

A novel continuous time integrated mixed notch and low pass filter is designed for multi standard biomedical applications like ECG, EMG, EEG etc. Since in biomedical signal processing the power line signal (50Hz/60Hz) has to be suppressed with notch filer and remaining low pass band has to be allowed through low pass filter. In this paper both notch filter and low pass filter is combined in one schematic. In order to get power line notch filter of 50 Hz and low pass filter of cutoff frequency less than 1 kHz, A Novel Bulk driven Operational Trans Conductance Amplifier (OTA) is used with 0.5 V supply in CMOS 180 nm Technology. The transconductance value of proposed OTA is less than 1 nS. In this paper the notch filter of sixth order attained notch depth of 75 dB with 280nWpower consumption and low pass filter of fourth order consumes around 200nW power.

I. Introduction

Nowadays ultra low frequency filters are using in many applications like hearing aid, wearable breathing detector, neural spike detector and etc [1]. However the biomedical processing and monitoring has to be precise and accurate. With a small noise in the biomedical signal may corrupt the original shape of the input bio medical informative signal. Hence proper filtering has to be needed. Table I shows the different biomedical signals like ECG(Electrocardiogram), EEG(Electroencephalogram), EMG (Electromyographic), etc and its frequency ranges [2]. Even though its frequency ranges are different, every signal can process using same set up is as shown in Fig. 1. Fig. 1:

Block diagram of biomedical signal processing system